For those who have neither their system online nor the lower versions of the
packages on their disk, these packages are attached to this post. Bring them
somehow (a pendrive, for instance) to the offline system, where, in a
terminal, you will move them to /var/cache/apt/archives (here assuming the
files are in the working directory):
$ sudo mv network-manager_1.2.6-0ubuntu0.16.04.3_amd64.deb
wpasupplicant_2.4-0ubuntu6.6_amd64.deb /var/cache/apt/archives
Then, chaosmonk's commands will work. Well, except that he forgot to mention
that NetworkManager must be restarted at the end:
$ systemctl restart NetworkManager
@chaosmonk: downgrading only NetworkManager was sufficient for my system, but
I imagine the reason to upgrade to a possibly less tested version of
wpa_supplicant was to get a newer version of NetworkManager, hence the advice
to downgrade both. Am I right?
